A new ecomaterial, zirconyl molybdopyrophosphate (ZMPP), was prepared by a coprecipitation method. The removal of Cs+ and Sr2+ ions from simulated strong acid HLLW using the ion exchange process on ZMPP had been investigated. It showed that there are more than 90% Cs+ and Sr2+ removed from the simulated HLLW on ZMPP despite the presence of other metal ions, such as Na+, Al3+, Fe3+, etc. in excess. Then ZMPP may likely be a selective ion exchanger for the removal of 137Cs and 90Sr directly from strong acid HLLW.
Zirconium in simulated high level radioactive liquid waste (HLLW) was selectively adsorbed and separated by self-made high adsorption activity silica gel. The selective adsorption mechanism was analyzed according to the structure character of self-made silica gel and performance of zirconium in acid simulated HLLW. The results show that the adsorption selectivity of self-made silica gel for zirconium is strong, because zirconium has higher positive charge and zirconium ion hydrolyzes easily. Distribution coefficient of self-made silica gels for zirconium is 53.5 ml/g. There are 6.5 (OH)/nm2 on the surface on self-made silica gels which provide more adsorption activity places, thus self-made silica gels have higher adsorption capacity for zirconium (31.4 mg/g). The elution rate of the adsorption of zirconium on self-made silica gel by 0.2 mol/l H2C2O4 is more than 99%. The solubility of the self-made silica gel in nitric acid is low, the chemical stability of self-made silica gel is very strong.
This study investigated the role of hydrogen sulfide (H2S) in the regulation of ascorbateglutathione (AsA-GSH) cycle by exogenous ABA in wheat leaves under osmotic stress. The results showed that osmotic stress significantly increased the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), the ratio of reduced ascorbate to oxidized ascorbate (AsA/DHA) and reduced glutathione to oxidized glutathione (GSH/GSSG), the malondialdehyde content and electrolyte leakage, and the H2S content, compared to control. Exogenous ABA significantly increased above indicators under osmotic stress, compared to osmotic stress alone. Above activity increases except MDHAR activity were suppressed by application of H2S scavenger hypotaurine (HT) and synthesis inhibitor aminooxyacetic acid (AOA). Meanwhile, exogenous ABA significantly decreased malondialdehyde content and electrolyte leakage induced by osmotic stress. Application of HT and AOA reversed above effects of application of exogenous ABA. Application of NaHS can reversed above effects of HT and AOA. Our results suggested that H2S induced by exogenous ABA is a signal that leads to the up-regulation of AsA-GSH cycle.
The crystallization dynamics of Nylon 66/Nylon 6
blends, the crystalline/crystalline polymer blends, was analyzed by DSC under
isothermal conditions. The crystal growth rate (G)
and the nucleation rate (N) depended on
both the degree of supercooling (ΔT)
and the blend mass fraction (ϕ). The ΔT
values obtained at the fixed G, which corresponded
to the chemical potential difference of molecules between liquid and crystal
states, and the surface free energy parameters evaluated from G
and N depended on ϕ for blends. The
results suggested that Nylon 66/Nylon 6 blends with ϕN66≥0.80
or ϕN66≤0.15 are miscible.
Authors:R. Liu, Q.N. Zhang, J. Lu, C.H. Zhang, L. Zhang, and Y. Wu
Salt stress is one of the major abiotic stress which severely limits plant growth and reduces crop productivity across the world. In the present study, the effects of exogenous pyridoxal-5-phosphate (vitamin B6, VB6) on seedling growth and development of wheat under salt stress were investigated. The results showed that exogenous application of pyridoxal-5-phosphate (VB6) significantly increased the RWC, biomass, the concentration of photosynthetic pigments, proline, the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), together with decreasing the content of Malondiadehyde (MDA) and hydrogen peroxide (H2O2) in wheat leaves under salt stress. Meanwhile, the transcript level of P5CR, P5CS, SOD, TaSOS1 and TaSOS4 were also up-regulated after treatment with pyridoxal-5-phosphate. VB6 acts as a signal in regulating the activities of plant antioxidant enzymes and SOS pathway to improve resistance to salt stress. The current study results may give an insight into the regulatory roles of VB6 in improving salt stress and VB6 could be an easily and effective method to improve salt-stress tolerance to wheat in the field condition. It is urgency to understand the molecular mechanism of VB6 to enhance the salt tolerance of wheat in the next work.
Authors:J. L. Zeng, L. X. Sun, F. Xu, Z. C. Tan, Z. H. Zhang, J. Zhang, and T. Zhang
In this paper, organic phase change materials (PCM)/Ag nanoparticles composite materials were prepared and characterized for the first time. The effect of Ag nanoparticles on the thermal conductivity of PCM was investigated. 1-tetradecanol (TD) was selected as a PCM. A series of nano-Ag-TD composite materials in aqueous solution were in-situ synthesized and characterized by means of thermal conductivity evaluation method, TG-DSC, IR, XRD and TEM. The results showed that the thermal conductivity of the composite material was enhanced as the loading of Ag nanoparticles increased. The composite materials still had relatively large phase change enthalpy. Their phase change enthalpy could be correlated linearly with the loading of TD, but their phase change temperature was a little bite lower than that of pure TD. The thermal stability of the composite materials was close to that of pure TD. It appeared that there was no strong interaction between the Ag nanoparticles and the TD. Furthermore, the experiment results indicated that the Ag nanoparticles dispersed uniformly in the materials, occurred in the forms of pure metal.
Authors:Y. Fan, Z. Gao, C. Bi, S. Xie, and X. Zhang
A new unsymmetrical solid Schiff base (LLi) was synthesized using L-lysine, o-vanillin and 2-hydroxy-l-naphthaldehyde. Solid lanthanum(III) complex of this ligand [LaL(NO3)]NO3·2H2O have been prepared and characterized by elemental analyses, IR, UV and molar conductance. The thermal decomposition kinetics
of the complex for the second stage was studied under non-isothermal condition by TG and DTG methods. The kinetic equation
may be expressed as: dα/dt=Ae−E/RT(1−α)2. The kinetic parameters (E, A), activation entropy ΔS# and activation free-energy ΔG# were also gained.
A new mixed C18-SCX SPE column and gas chromatography-mass spectrometry have been used for determination of six β2-agonists residues in pig's liver. After hydrolysis, the six β2-agonists were extracted with 6:4 (v/v) ethyl acetate-isopropanol and then cleaned on a commercial mixed-adsorbent solid-phase extraction column. The eluted solution was analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified by the external standard method. Sample pre-treatment and GC-MS conditions were critically examined. The linear range was 0.005–2.00 mg L–1 and correlation coefficients were 0.9987–1.000. The LOD of mabuterol, clenbuteroland, and salbutamol was 0.2 μg kg–1. Average recoveries of these three compounds from spiked pig's liver ranged from 65.3 to 95.8% and relative standard deviations were between 5.4 and 9.9%. The LOD of cimaterol, bromobuterol, and ractopamine was 0.3 μg kg–1. Average recoveries of these three compounds from spiked pig's liver ranged from 63.8 to 88.1% and relative standard deviations were between 5.0 and 9.7%. These results indicate the method is highly sensitive, simple, inexpensive, and results in good purification. It could also meet requirements for analysis of pig's urine in domestic and import/export inspection work.
Authors:X. Cai, H. Shen, C. Zhang, Y. Wang, and Z. Kong
A simple operation mode to determine the apparent activation energy Ea is introduced. Ea can be determined with a double-curve method by using a constant reaction rate (CRR) approach of Hi-Res TG. The most appropriate
mechanism function f(α) and frequency factor A are determined by a single-curve method when the activation energies provided by the two methods are in good agreement with
each other. The deacetylation of EVA copolymer has been used for illustration. Advantages of the CRR are discussed.